Theorem exmo 1042

Description: Something exists or at most one exists.

Assertion

Ref	Expression
exmo	|- (E.xph \/ E*xph)

Proof of Theorem exmo

Step	Hyp	Ref	Expression
1		pm2.21 71	. . 3 |- (-. E.xph -> (E.xph -> E!xph))
2		df-mo 1010	. . 3 |- (E*xph <-> (E.xph -> E!xph))
3	1, 2	sylibr 175	. 2 |- (-. E.xph -> E*xph)
4	3	orri 201	1 |- (E.xph \/ E*xph)

Syntax hints:  -. wn 1   -> wi 2   \/ wo 195  E.wex 678  E!weu 1007  E*wmo 1008

This theorem is referenced by:  moexex 1058  mo2icl 1434  mosubop 1911

This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6

This theorem depends on definitions:  df-bi 128  df-or 197  df-mo 1010

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